Apparatus for plating aluminum on wire

ABSTRACT

Apparatus for plating an elongated metal member, such as a wire, with a coating of a metal capable of being incorporated in a liquid plating solution. The wire is passed lengthwise through a bath of, for example, an aluminum alkyl liquid. A heating zone is provided in the bath, as by means of an induction coil surrounding a portion of the path of movement of the wire, or by resistance heating of the wire. Means are provided for displacing the aluminum alkyl liquid from around that portion of the wire in the entry end portion of the heating zone, such that the wire will be heated to the desired plating temperature prior to the time the heated wire is exposed to the aluminum alkyl liquid to provide a thick coating of aluminum on the wire in a single pass through the bath.

United States Patent 72] Inventors I Larry ll. Hood;

Le Roy Rose; Charles M. Starks, all of Ponca City, Okla. [2]] Appl. No. 25,696 [22] Filed Apr. 6, 1970 [45] Patented Nov. 16, 1971 [73] Assignee Continental Oil Company Ponca City, Okla.

[54] APPARATUS FOR PLATING ALUMINUM 0N WIRE 14 Claims, 2 Drawing Figs.

[52] US. Cl 118/620, 219/1075, l l8/DlG. l9 [5 1] Int. Cl B05c 5/00 [50] Field of Search 1 14/405. 620; ll7/3.2, 33,102, 227; 219/1075, 76

[56] Referenea Cited UNITED STATES PATENTS 2,079,867 5/1937 Meyers l 18/620 2,502,770 4/1950 Watson l 18/620 3,227,577 H1966 Baessler et al. 118/405 X 3,282,249 I 1/1966 Ramsay 1 18/620 3,424,130 [/1969 Byrnes et al. 1 18/405 3,483,030 12/1969 Clarke H 1 17/227 Primary Examiner- Louis K. Rimrodt Attorneys-Joseph C. Kotarski. Henry H. Huth. Robert B Coleman. Jr. and Carroll Palmer ABSTRACT: Apparatus for plating an elongated metal member, such as a wire. with a coating of a metal capable of being incorporated in a liquid plating solution. The wire is passed lengthwise through a bath of, for example, an aluminum alkyl liquid. A heating zone is provided in the bath, as by means of an induction coil surrounding a portion of the path of movement of the wire, or by resistance heating of the wire. Means are provided for displacing the aluminum alkyl liquid from around that portion of the wire in the entry end portion of the heating zone. such that the wire will be heated to the desired plating temperature prior to the time the heated wire is exposed to the aluminum alkyl liquid to provide a thick coating of aluminum on the wire in a single pass through the bath.

APPARATUS FOR PLATING ALUMINUM ON WIRE BACKGROUND OF THE INVENTION l Field of the Invention This invention relates to an improved apparatus for plating elongated metal members, and more particularly, but not by way of limitation, to an improved apparatus for plating aluminum on wire.

2. Description of the Prior Art Many techniques for plating elongated metal members, including plating aluminum on wire, have been proposed. In the majority of the prior art techniques, the wire is alternately heated and immersed in the plating solution, such as an aluminum alkyl solution, in a cyclic fashion until the desired thickness of coating is obtained. This cyclic type of technique requires an undue length of time and if the partially coated wire is not maintained in an inert atmosphere between the immersion steps, an oxide layer tends to form on the previously deposited aluminum which is detrimental to the completed coating. Prior to the present invention, no apparatus has been provided to produce the desiredthickness of coating in a single pass of the wire through the plating solution.

SUMMARY OF THE INVENTION An object of this invention is to provide an apparatus for plating an elongated metal member in a continuous fashion and in a minimum of time.

Another object of this invention is to produce a coating on an elongated metal member with a single immersion of the member in the plating solution.

A further object of this invention is to control the heating of an elongated metal member immediately prior to and during coating of the member to provide the desired thickness of coating.

A still further object of this invention is to heat an elongated metal member to be plated while the member is submerged in the plating solution to conserve the amount of heat required and to speed up the coating operation.

Another object of the invention is to provide a simply constructed apparatus for coating elongated metal members which may be economically manufactured.

Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawing illustrating two embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a schematic illustration of one embodiment of the invention in the nature of a vertical sectional view through the apparatus.

FIG. 2 is a similar illustration of another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing in detail, and particularly FIG. 1, reference character 10 designates a bath of the plating solution, such as an aluminum alkyl liquid, which will be contained in a suitable vessel (not shown). The elongated metal member 12, such as a steel wire, to be coated is extended from a supply roll 14 downwardly into the bath l underneath an idler roller 16 and then extends along a straight path through the bath underneath another idler roller 18 prior to being extended upwardly out of the bath to a takeup roll 20. The supply roll 14 and takeup roll 20 may be operated by any desired mechanism to move the wire 12 through the bath 10 at the desired speed, as is well known in the art.

An induction heating coil 22 is immersed in the bath l0 and surrounds the path of movement of the wire 12 through a portion of the distance between the idler rollers 16 and 18 to form what may be considered a heating zone in the bath. The lefthand end 24 of the coil 22, as viewed in the drawing, may be considered the entry end of the heating zone and the righthand end 26 may be considered the discharge end of the heating zone, since the wire 12 is moved from the lefl to the right as viewed in the drawing. The induction coil 22 is connected to a suitable adjustable power supply for controlling the current supplied to the coil and thereby inductively heat the wire 12 to the desired plating temperature.

A tube 28 of inert material, such as glass, having apertures 30 and 32 in the opposite ends thereof, extends into the entry end 24 of the coil 22, with the wire 12 extending lengthwise through the tube and through the apertures 30 and 32. In a preferred construction, the tube 28 is of a size to slidingly fit in the coil 22 and thereby be at least primarily supported by the coil 22 in the bath 10. A conduit 34 extends from the tube 28 adjacent the end thereof removed from the coil 22 and is connected to the tube 28 such that the interior of the conduit 34 communicates with the interior of the tube 28. An inert gas, such as nitrogen, is supplied to the conduit 34, as through a flexible tubing 36 of inert material, to purge the aluminum alkyl liquid from the tube 28.

In view of the fact that the rate of heat transfer away from the wire 12 is greater when the wire is surrounded by the aluminum alkyl liquid than is the case when the wire is surrounded with the inert gas, the wire passing through that portion of the heating zone which includes the tube 28 is heated quickly and is brought to the desired plating temperature prior to the time the heated wire is exposed to the aluminum alkyl liquid. That portion of the heating zone beyond the tube 28 (to the right as shown in the drawing) will maintain the wire 12 at the desired plating temperature with the result that the desired amount of aluminum from the bath is deposited on the wire to completely coat the wire. It will be appreciated that the farther the tube 28 extends into the coil 22, the greater length of time the wire 12 will be exposed to the more efficient heating condition in the tube 28. When the wire is to be plated with aluminum from an aluminum alkyl liquid, the wire should be heated from about 50 C. to about 650 C., and the higher the temperature within this range, the more aluminum will be deposited on the wire. Therefore, the tube 28 may be extended into the coil 22 at varying distances to control the temperature of the wire as it leaves the tube and thereby control the thickness of the coating applied to the wire. As previously indicated, that portion of the coil 22 between the tube 28 and the discharge end 26 of the heating zone will maintain the wire 12 at the desired plating temperature as the aluminum is being deposited on the wire.

The position of the tube 28 in the coil 22 may be controlled by any desired adjusting mechanism. For example, a clamp 38 may be secured around the conduit 34 and connected to a cable 40. The cable 40 is preferably passed through a wound wire sleeve 42 in order that the cable 40 will be constrained to move lengthwise when either pushed or pulled, and the cable 40 is extended to the exterior of the vessel containing the bath 10 for manipulation by the operator of the apparatus as desired. Also, a stationary bracket 44 should be provided in the vessel to maintain the cable 40 in alignment with the desired direction of movement of the tube 28 so that when the operator pushes on the cable 40 the tube 28 will be moved farther out of the coil 22, and when the operator pulls on the cable 40, the tube 28 will be inserted farther into the coil 22. The cable 40 may be easily selected to provide sufficient support for the end of the tube 28 remote from the coil 22.

It should also be noted that an atmosphere of inert gas, such as nitrogen, should be maintained above the level of the bath I0, and the required gas for maintaining this atmosphere is obtained by the gas being discharged through the apertures 30 and 32 at the opposite ends of the tube 28.

The heating of the wire while the wire is submerged in the plating solution greatly facilitates the precision in control of the temperature to which the wire is heated when exposed to the plating solution, such that the desired thickness of coating is obtained in a single pass of the wire through the plating solu tion. If desired, multiple tubes 28 and coils 22 may be provided in the same bath 10 in spaced relation along the path of movement of the wire 12 to deposit the aluminum in layers on the wire. It will be apparent that the member being plated will be plated in a minimum of time; the required apparatus is simple in construction and may be economically manufactured, and the apparatus will require a minimum amount of total heat.

EMBODIMENT OF FIG. 2

The wire 12 being coated may be heated to plating temperature in the bath by means of resistance heating as shown in FIG. 2, rather than induction heating as previously described.

in using resistance heating, a wiper 50 contacts the wire 12 at what may be considered the entry end of the heating zone, and a second wiper 52 contacts the wire 12 at what may be considered the discharge end of the heating zone. The wipers 50 and 52 may be constructed in any desired manner and supported in the vessel containing the bath to remain in contact with the wire as the wire is moved lengthwise through the bath in the manner previously described. The wipers 50 and 52 are connected to a suitable source of electrical energy such as a variable power supply 54.

When resistance heating is employed, the inert tube used for displacing the plating solution from around the wire in the entry end portion of the heating zone is preferably formed in two telescoping sections 28a and 28b, rather than being a unitary structure as previously described. The tube section 28b has the aperture 32 in one end 56 thereof to receive the wire 12 and is supported in a fixed position in the bath 10 by a suitable clamp 58 in such a position that the centerline of the tube section 28b substantially corresponds with the path of movement of the wire 12. One end 60 of the other tube section 28a is slidingly supported in the opposite end 62 of the tube section 28b. The opposite end 64 of the section 28a contains the aperture 30 for receiving the wire 12, and the section 28a is connected to the conduit 34 which is, in turn, connected to a source of inert gas under pressure in the same manner as described in connection with FIG. 1.

With the arrangement shown in FIG. 2, the length of that portion of the wire 12 from which the plating solution is displaced by inert gas may be easily controlled by moving the tube section 28a fartherinto and farther out of the tube section 28b and thereby control the temperature to which the wire 12 is heated prior to being exposed to the plating solution upon discharge from the aperture 32 to obtain the desired coating of the wire in a manner similar to that previously described. The tube section 28a may be controlled by a cable connected to the conduit 34 in the same manner as previously described in connection with the embodiment shown in FIG. I. Thus, the wire 12 may be heated to the desired plating temperature while submerged in the plating solution.

It is believed apparent that the present invention will provide the objectives heretofore set forth.

Changes may be made in the combination and arrangement of parts or elements as heretofore set forth in the specification and shown in the drawing without departing from the spirit and scope of the invention as defined in the following claims.

What is claimed is:

1. Apparatus for plating an elongated metal member with a coating of metal capable of being incorporated in a liquid plat ing solution, comprising:

a bath of the liquid plating solution;

means for moving the elongated metal member lengthwise through the bath;

means forming a heating zone in the bath along a portion of the path of travel of the elongated metal member through the bath having an entry end and a discharge end for heating the elongated metal member to a temperature at which the plating metal will deposit out of the plating solution onto the elongated metal member; and

means for displacing the plating solution from around the elongated metal member in the entry end portion of the heating zone with an inert gas, whereby the elongated metal member is preheated to coating temperature while submerged in the bath and prior to being coated with the plating metal.

2. Apparatus as defined in claim 1 wherein the means forming a heating zone in the bath comprises an induction heating coil surrounding a portion of the path of travel of the elongated metal member.

3. Apparatus as defined in claim 2 wherein the means for displacing the plating solution from around the elongated metal member in the entry end of the heating zone comprises:

a tube having openings at the opposite ends thereof through which the elongated metal member passes and having one end thereof extending into the end portion of the induction heating coil forming the entry end portion of the heating zone, said tube being formed ofa material inert to the plating solution; and

means for feeding the inert gas to the tube at a pressure sufficient to displace the plating solution from the tube.

4. Apparatus as defined in claim 3 characterized further to include means for adjusting the distance the tube extends into the induction heating coil.

5. Apparatus as defined in claim 3 wherein the induction heating coil is stationary, the tube slidingly fits in the induction heating coil, and characterized further to include means connected to the tube for moving the tube lengthwise to adjust the distance the tube extends into the induction heating coil.

6. Apparatus as defined in claim 4 wherein the induction heating coil is stationary, the tube slidingly fits in the induction heating coil, and said last-mentioned means comprises a cable connected to the tube and extending to a position remote from the bath, and means for guiding the cable in a direction to move the tube lengthwise.

7. Apparatus as defined in claim 3 wherein the tube is a glass tube.

8. Apparatus for coating a wire with aluminum, comprising:

a bath of an aluminum alkyl liquid;

means for moving the wire lengthwise through the bath in a path at least a portion of which is straight;

means in the bath forming a heating zone along a portion of said straight path for heating the wire to a plating temperature of from about 50 to about 650 C., said heating zone having an entry end and a discharge end for the wire; and

means for displacing the aluminum alkyl liquid from around the wire in the entry end portion of the heating zone with an inert gas, whereby the wire is brought to plating temperature in the entry end of the heating zone prior to exposure ofthe heated wire to the aluminum alkyl liquid.

9. Apparatus as defined in claim 8 wherein the means forming a heating zone comprises an elongated induction heating coil surrounding the path of movement of the wire.

10. Apparatus as defined in claim 9 wherein the means for displacing the aluminum alkyl liquid from around the wire in the entry end portion of the heating zone comprises a tube of inert material through which the wire passes, and means for feeding the inert gas to the tube under sufiicient pressure to displace the aluminum alkyl liquid from the tube.

11. Apparatus as defined in claim 10 wherein the tube is slidingly supported in the induction heating coil, whereby the position of the tube may be adjusted to vary the distance the tube extends into the induction heating coil, and, thus, adjust the temperature of the wire prior to exposure of the heated wire to the aluminum alkyl liquid.

12. Apparatus as defined in claim 8 wherein the means forming a heating zone comprises a wiper contacting the wire at the entry end of the heating zone and a wiper contacting the wire at the discharge end of the heating zone, and a source of electrical energy connected to the wipers.

13. Apparatus as defined in claim 12 wherein the means for displacing the aluminum alkyl liquid from around the wire in the entry end portion of the heating zone comprises a tube of inert material through which the wire passes, and means for feeding the inert gas to the tube under sufficient pressure to displace the aluminum alkyl liquid from the tube.

6 14. Apparatus as defined to claim 13 wherein the tube of means for sliding the other tube section relative to the firstinert material is in two telescoping sections, and characterized mentioned tube i n t vary the effective length of the further to include: tube, whereby the temperature of the wire may be ad means for supporting one of the tube sections in a fixed j position; and 5 

1. Apparatus for plating an elongated metal member with a coating of metal capable of being incorporated in a liquid plating solution, comprising: a bath of the liquid plating solution; means for moving the elongated metal member lengthwise through the bath; means forming a heating zone in the bath along a portion of the path of travel of the elongated metal member through the bath having an entry end and a discharge end for heating the elongated metal member to a temperature at which the plating metal will deposit out of the plating solution onto the elongated metal member; and means for displacing the plating solution from around the elongated metal member in the entry end portion of the heating zone with an inert gas, whereby the elongated metal member is preheated to coating temperature while submerged in the bath and prior to being coated with the plating metal.
 2. Apparatus as defined in claim 1 wherein the means forming a heating zone in the bath comprises an induction heating coil surrounding a portion of the path of travel of the elongated metal member.
 3. Apparatus as defined in claim 2 wherein the means for displacing the plating solution from around the elongated metal member in the entry end of the heating zone comprises: a tube having openings at the opposite ends thereof through which the elongated metal member passes and having one end thereof extending into the end portion of the induction heating coil forming the entry end portion of the heating zone, said tube being formed of a material inert to the plating solution; and means for feeding the inert gas to the tube at a pressure sufficient to displace the plating solution from the tube.
 4. Apparatus as defined in claim 3 characterized further to include means for adjusting the distance the tube extends into the induction heating coil.
 5. Apparatus as defined in claim 3 wherein the induction heating coil is stationary, the tube slidingly fits in the induction heating coil, and characterized further to include means connected to the tube for moving the tube lengthwise to adjust the distance the tube extends into the induction heating coil.
 6. Apparatus as defined in claim 4 wherein the induction heating coil is stationary, the tube slidingly fits in the induction heating coil, and said last-mentioned means comprises a cable connected to the tube and extending to a position remote from the bath, and means for guiding the cable in a direction to move the tube lengthwise.
 7. Apparatus as defined in claim 3 wherein the tube is a glass tube.
 8. Apparatus for coating a wire with aluminum, comprising: a bath of an aluminum alkyl liquid; means for moving the wire lengthwise through the bath in a path at least a portion of which is straight; means in the bath forming a heating zone along a portion of said straight path for heating the wire to a plating temperature of from about 50* to about 650* C., said heating zone having an entry end and a discharge end for the wire; and means for displacing the aluminum alkyl liquid from around the wiRe in the entry end portion of the heating zone with an inert gas, whereby the wire is brought to plating temperature in the entry end of the heating zone prior to exposure of the heated wire to the aluminum alkyl liquid.
 9. Apparatus as defined in claim 8 wherein the means forming a heating zone comprises an elongated induction heating coil surrounding the path of movement of the wire.
 10. Apparatus as defined in claim 9 wherein the means for displacing the aluminum alkyl liquid from around the wire in the entry end portion of the heating zone comprises a tube of inert material through which the wire passes, and means for feeding the inert gas to the tube under sufficient pressure to displace the aluminum alkyl liquid from the tube.
 11. Apparatus as defined in claim 10 wherein the tube is slidingly supported in the induction heating coil, whereby the position of the tube may be adjusted to vary the distance the tube extends into the induction heating coil, and, thus, adjust the temperature of the wire prior to exposure of the heated wire to the aluminum alkyl liquid.
 12. Apparatus as defined in claim 8 wherein the means forming a heating zone comprises a wiper contacting the wire at the entry end of the heating zone and a wiper contacting the wire at the discharge end of the heating zone, and a source of electrical energy connected to the wipers.
 13. Apparatus as defined in claim 12 wherein the means for displacing the aluminum alkyl liquid from around the wire in the entry end portion of the heating zone comprises a tube of inert material through which the wire passes, and means for feeding the inert gas to the tube under sufficient pressure to displace the aluminum alkyl liquid from the tube.
 14. Apparatus as defined to claim 13 wherein the tube of inert material is in two telescoping sections, and characterized further to include: means for supporting one of the tube sections in a fixed position; and means for sliding the other tube section relative to the first-mentioned tube section to vary the effective length of the tube, whereby the temperature of the wire may be adjusted. 